Corneal transparency depends on a unique extracellular matrix secreted by stromal keratocytes, mesenchymal cells of neural crest lineage. Derivation of keratocytes from human embryonic stem (hES) cells could elucidate the keratocyte developmental pathway and open a potential for cell-based therapy for corneal blindness. This study seeks to identify conditions inducing differentiation of pluripotent hES cells to the keratocyte lineage. Neural differentiation of hES cell line WA01(H1) was induced by co-culture with mouse PA6 fibroblasts. After 6 days of co-culture, hES cells expressing cell-surface NGFR protein (CD271, p75NTR) were isolated by immunoaffinity adsorption, and cultured as a monolayer for one week. Keratocyte phenotype was induced by substratum-independent pellet culture in serum-free medium containing ascorbate. Gene expression, examined by quantitative RT-PCR, found hES cells co-cultured with PA6 cells for 6 days to upregulate expression of neural crest genes including NGFR, SNAI1, NTRK3, SOX9, and MSX1. Isolated NGFR-expressing cells were free of PA6 feeder cells. After expansion as a monolayer, mRNAs typifying adult stromal stem cells were detected, including BMI1, KIT, NES, NOTCH1, and SIX2. When these cells were cultured as substratum-free pellets keratocyte markers AQP1, B3GNT7, PTDGS, and ALDH3A1 were upregulated. mRNA for keratocan (KERA), a cornea-specific proteoglycan, was upregulated more than 10,000 fold. Culture medium from pellets contained high molecular weight keratocan modified with keratan sulfate, a unique molecular component of corneal stroma. These results show hES cells can be induced to differentiate into keratocytes in vitro. Pluripotent stem cells, therefore, may provide a renewable source of material for development of treatment of corneal stromal opacities.

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, often underrecognized, low-grade sweat gland carcinoma of the skin of the eyelid. To date, only 20 cases of this carcinoma have been reported, most frequently in Caucasian females with an average age of 70 years. Although the diagnosis is primarily made with immunohistochemical stain, compared to endocrine ductal carcinoma in situ, clinical detection serves as a potentially curative treatment. Further, its benign appearance clinically makes this tumor often misdiagnosed and undertreated. This disease commonly presents in Caucasian women of advanced age, aiding in the diagnosis of this tumor, which presents an even more critical diagnosis in a patient with a rare presentation. In the available literature, we could find no case of EMPSGC in younger African American women. The following case is the first case presented in the literature. Here, we present a case of an atypical presentation of the tumor in a young African American female, as well as a review of literature on the pathophysiology, clinical presentation, and treatment of EMPSGC.